Well bores can be drilled into the earth to tap into underground reservoirs of oil or gas. Such well bores can be lined with a casing (e.g., a metal casing) to add structural stability to the well bores. Well bores are typically abandoned after use. In some cases, a well bore may be abandoned and closed after the volume of oil or gas produced by the well drops below suitably economical levels. Alternatively, in some cases, a well bore is abandoned and closed as a result of a loss of control (blowout) in a well bore. Different regulatory bodies have different requirements for such abandoning operations. Some regulatory bodies require that the abandoned well bore be plugged (e.g., with cement plugs).